Circuit interrupter



July 28, 1953 J. M. WALLACE Erm.. 2,647,183

CIRCUIT INTERRUPTER BY l K 9`l l f I0 12 @f4 l/ ATToRN July 23, 1953 J. M. WALLACE Erm. 2,647,183

CIRCUIT INTERRUPTER Original Filed June 14, 1944 2 Sheets-Sheet 2 INVENTORS Jams 7. Wal/ace may? Alvi/2 1^/ gg.

@Nm v w24 Patented July 28, 1953 CIRCUIT INTERRUPTER James M. Wallace, East McKeesport, and Alvin W. Ogg, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Continuation of application Serial No. 540,192,y

June 14, 1944. This application July 27, 1948,

Serial No. 40,958

11 Claims.

This invention relates to electric circuit interrupters in general, and, more particularly, to circuit interrupters which automatically operate to reclose the circuit following a circuit interrupting operation, with this application being a continuation of our application Serial No. 5fi0,192, led June 14, 1944, on the same subject and assigned to the same assignee as this invention.

In circuit interrupters of the type having electroresponsive means for separating the interrupter contacts which are biased into engagement in order to automatically reclose the circuit, a pumping action of the contacts has been encountered under conditions Where the electrical condition to which the contact separating means responds is relatively small. These conditions cause an initial separation of the contacts, but before the contacts can separate any appreciable amount, interruption occurs and the contacts immediately reclose, usually before time delay means Aprovided for controlling the speed of reclosure,

and before integrating means usually provided for preventing more than a predetermined numf ber of successive reclosings, can operate, If such a relatively small electrical condition persists, the 'contacts will continue to rapidly open and close, "and this not only results in excessive arcing, but

no opportunity is given for such a condition to clear itself. What may hap-pen then is that the pumping action continues until the interruptor destroys itself.

One object of this invention is to prevent pumping in a circuit interrupter of the type described,

by providing novel means actuated by e1ectro' responsive means for causing the interrupter con- .tacts to separate at least a predetermined distance on each circuitv opening operation which is sufiicient to introduce a predetermined time ldelay before the circuit is reclosed.

Another object of this invention is to provide in an automatic reclosing circuit interruptor of the type described, overcenter spring means .adapted to be operated over center by electrovresponsive means to open the interrupter contacts at least a predetermined amount on each :circuit opening operation.

One complication that arises in providing any :means for obtaining at least a predetermined amount of contact separation at a predetermined' rate independent of the rate of movement or force exerted by electroresp-onsive actuating means, is that the amount of contact separation varies in some interrupters with the value of current interrupted. In other Words, the greater the current interrupted, the greater the separation of the contacts. In order to accommodate such variable contact separation, it is necessary `that the circuit opening .means be -associated with the contacts in a manner to permit them to operate free of the opening mechanism, at least on interruption of high currents. f

Accordingly, another object of this inventio is to provide in an automatic reclosing circuit interrupter of the type described, novel means actuated by electroresponsive means for causing the interrupter contacts to separate at least a predetermined amount on each circuit interrupting operation, with provision for further separation of the contacts independent of the opening means.

Another object of this invention is to provide in an automatic reclosing circuit interruptor, separable contacts which are held closed under predetermined contact pressure, and electroresponsive means to separate the contacts by first storing energy at a rate determined by the magnitude of the electrical condition to which it responds, and then releasing the stored energy when a predetermined amount `oi" energy has been stored to rapidly separate the contacts at least a predetermined amount on each circuit interrupting operation.

Another object of this invention is to provide snap-acting mechanism vdirectly engaging the movable contact of a circuit interrupter to open the circuit with a snap action, wherein the mechanism releases the movable contact after predetermined opening movement of the contact to permit continued opening movement of the movable contact independent of the mechanism.

- The provision of a means for obtaining at least a predetermined amount of contact separation on each circuit interrupting operation in a circuit interrupter of the type which automatically re- 'clos'es after each circuit interrupting operation, 'also requires provisions for resetting the opening means so that on a succeeding circuit interrupt- 'ing operation, the same predetermined contact Aseparation will be obtained. f

Accordingly, still another object of this invention is to provide in an automatic reclosing circuit interruptor, means for obtaining at least a predetermined contact separation on each circuit kopening operation of the interrupter, with novel means responsive to automatic reclosure of the interrupter to reset the circuit opening means `so that the same predetermined contact separation vvill be obtained on the next succeeding interrupting operation.

These and other objects of this invention Will j become more apparent upon consideration of the following detailed description of preferred embodiments thereof when taken in connection with 'the attached drawings, in which:

Figure 1 is a side elevation view of an automatic reclosing circuit breaker constructed in 3 accordance with this invention, with part of the breakerA casing broken away to illustrate the interior construction, some of which is shown in section;

Fig. 2 is an enlarged, partial elevational view of the breaker operating mechanism shown in Fig. l looking from the left of Fig. 1;

Fig. 3 is a side elevation view of the mechanism shown in Fig. 2, with the parts at the position occupied when the breaker contacts are open;

Fig. 4.- is an elevational view, partially in section, of a modified form of actuating mechanism for use with a circuit breaker like that shown in Fig. 1;

Fig. 5 is a partial elevational view of the mechanism shown in Fig. 4, looking from the right of Fig. 4;

Fig. 6 is a partial side elevation view of still another modified form of breaker operating mechanism; and

Fig. 7 is another elevation view oi the mechanism shown in Fig; 6, but with the parts located at the position they occupy when the breaker contacts are open.

The circuit breaker shown in Fig. l is preferably mounted in a tubular casing 2 of insulating material, such, for example, as porcelain or the like. The casing 2 may be mounted on a support by means of a bracket 4 secured about the easing substantially at the mid-portion thereof. The casing 2 is preferably provided with a closed bottom which is apertured for the reception of a terminal bolt 6 having an enlarged head 8 adapted to be seated on a gasket |5 with in casing 2. A nut itl is adapted to secure the terminal bolt in position, and also to secure a terminal strap l2 in conductive relation with the bolt, so that a line conductor may be electrically connected therewith by means of a terminal socket i The top of casing 2 is preferably open, and a cover casting I8 is seated on the open top of casing 2. Cover casting |3 preferably has a fiange adapted to seat on gasket provided on the top of casing 2, and the cover casting may be secured to casing 2 in any desired manner,

such, for example, as by securing means (not -leg portions thereof rotatably mounted on shaft 28, and the spring support 36 is biased to rotate in a counterclockwise direction by a coil compression spring 32. A spring supporting rod 34 is provided for spring 32, with the spring mounted on the rod and reacting between a collar 36 fixed to supporting rod 34, and an apertured ear 3S provided integral with the cover casting. The spring supporting rod 34 is pivoted to spring support as at 40, so that in biasing rod 34 to the left, as viewed in Fig. 1, the spring support 30 is biased to rotate counterclockwise. Normally counterclockwise rotation of spring support 30 is prevented by an overcenter toggle comprising a link 'i pivotally connected with the spring support as at et, and with another toggle link 44 by a pivot 48. Toggle link 44 is pivotally mounted in the cover casting as at 50, and is provided with an integral extension 52 which is normally held by spring 32 in engagement with an adjustable stop screw 54 threadedly mounted in a hood portion 56 integral with cover casting I8. Extension 52 of toggle link 54 is provided at its outer end with a hook-eye aperture 6D for the reception of a hook-stick operating member or the like.

Spring support 30 is also adapted to cooperate with a coil spring 62 wound about shaft 28, with one end 64 of the spring engaging spring support 30, and the other end 66 thereof engaging an actuating crank 88 pivotally mounted on shaft 28. Actuating crank 68 is adapted to be connected by a pair of links l0 of insulating material, such, for example, as fiber or the like, with a head |54 xed on the upper end of a contact actuating rod 16. The connecting links 'l0 are pivoted to actuating crank 68 as at l2, and to head |64 by pivot pin 14.

The breaker contacts are mounted in the lower portion of casing 2 within an arc chamber 18 formed by a cylindrical tube 8G of insulating material, such as fiber or the like, having a top cap 82 threadedly mounted on one end thereof, and a bottom cap 84 threaded on the other end thereof. A current-carrying compression spring 86 is adapted to be compressed between a shoulder provided on the bottom cap of arc chamber 'I8 and head 8 of terminal bolt 6, to carry current from thelower terminal of the casing to the bottom cap of arc chamber 18. Bottom cap S4 of the are chamber is provided with a central opening for receiving a contact screw 88, which is secured in operative position by a lock nut 90. Bottom cap 84 of the arc chamber is also provided with spaced inlet apertures 92, which may be covered by a valve disk 94 loosely mounted in the vlower part of the arc chamber. A stop ring 96 is clamped between bottom cap 84 of the arc chamber and the lower end of tubular member 80, for a purpose to be described. The top cap 82 for the arc chamber is provided with a plurality of outlet apertures 98, adapted to be controlled by a valve plate |00, normally biased to uncover the outlet apertures by a compression spring |02.

The lower end of contact actuating rod 16 is provided with a contact tip |04 secured thereto, and it has a contact head at the lower end thereof for engagement with contact screw 88 in the closed position of the cir-cuit breaker. A liquid director |08 is slidably mounted on contact tip |04, and in the closed circuit position is biased against stop ring 36 by a compression spring ||0 reacting between the contact actuating rod 16 and the liquid director.

In service, casing Z is preferably filled with an arc-extinguishing liquid up to a level located at the upper end oi the casing adjacent ring 22. Accordingly, the arc chamber is submerged in such liquid, and will be filled with arc-extinguishing liquid at all times. It will be noted that in the structure described above, the movable contact |86 is continuously biased towards stationary contact E8, so that whenever there is no force exerted on contact |06 tending to move it away from contact 88, biasing spring 62 will cause engagement of the contacts and consequent closure oi the circuit. If movable contact |06 be separated from fixed contact E8, an arc will be formed within arc chamber 'I8 which will act on the arc-extinguishing fluid therein to produce gases and build up a pressure within the arc- 'extinguishing chamber.

This pressure within chamber 'I8 causes valve disk 94 and valve plate |00 to seal to inlet and outlet openings, and the pressure will act on the movable contact rod in a piston-like manner to cause further separation of the contacts. This separation of the contacts will continue until the arc is extinguished. As soon as the arc is extinguished within arc chamber "I8, the pressure will decrease, and outlet openings 98 will be uncovered by movement of valve plate |00 downwardly under the iniluence of spring |02. This permits the escape of gases from the arc chamber and permits inflow of fresh liquid through inlet openings S2, so that a flushing of the arc chamber will automatically occur after each circuit interruptingoperation.

It will be observed that the contact closing bias of spring 62 may be destroyed and the breaker contacts open-ed, by collapsing toggle levers 42 and 44, as by rotating` toggle lever extension 52 in a clockwise direction. r,This moves toggle links 42 and 44 overcenter, and permits spring 32 to move spring support 30 counterclockwise thus removing the support for the end 64 of biasing spring 62. Rotation of spring support 30 in a counterclockwise direction by spring 32, also causes it to engage the end 69 of crank 68 and hold it in a position wherein contact |06 is out of engagement with iixed contact 88. Obviously, the toggle levers 42 and 44 may be moved overcenter back to the position shown in Fig. 1, by merely rotating the toggle extension 52 in a counterclockwise direction back to the position shown in Fig. 1. This will relatch spring support 30 in the position shown, and permit biasing spring 62 to close the breaker contacts.

Preferably, contact actuating rod 76 is provided with a sleeve of insulating material ||2 within arc chamber 80 which covers the actuating rod in its passage through the top cap 82 of the interrupter chamber. This sleeve of insulation serves to separate the contact actuating rod from a tubular core ||4 of magnetic material, which is adapted to be attracted by a solenoid coil ||8 mounted in a supporting frame I|6 secured to the upper end of the arc chamber. The supporting frame ||6 preferably has at least one side thereof open to permit insertion of the solenoid coil H8, which is annular in form. A dashpot cylinder sleeve |20 is centrally mounted in supporting frame H6, and serves to properly locate coil I |8, and is secured in position in alignment with apertures through the top and bottom of frame I I 6 by a collar 22, threaded into theraperture through the top of frame Il'. Dashpot cylinder |20 is provided with an integral inwardly extending stop flange |125, for limiting upward movement of tubular core ||4. Core |54 is connected at its upper end with the lower end of an actuating sleeve |36 slidably mounted on actuating rod 16, and the two sleeves are normally biased downwardly by a coil compression spring |24 reactingbetween collar |22 and the juncture between the sleeves. Collar |22 is preferably provided with a restricted vent aperture |28 for limiting the rate at which fluid escapes from dashpot cylinder |20.

The upper end of actuating sleeve |36 is provided with a collar |32 for connection to a contact actuating mechanism supported between spaced supporting plates |34, preferably secured at their upper ends to cover casting I3, and joined at their lower ends, by a connecting strap |36, to solenoid supporting frame H6, preferably in insulated relation, as by washers of insu- 6 lating material (not shown) interposed between plates |34 and cover casting |8. The contact actuating mechanism includes a generally U shaped lever |38 pivotally mounted as at |40 on supporting plates |34, and connected with collar |32 of actuating sleeve |30, by a pair of connecting links |42 pivoted to the collar as at |46 and to the U-shaped lever as at |44. Lever |38 is adapted to control an overcenter tension spring |48, having one end hooked over a pin I 5| on the lever, and the other end hooked over a pin mounted between generally triangular-shaped links |52. The triangular-shaped links |52 are preferably joined at one side by an integral connecting strip |53, and are pivotally mounted on extensions |55 of supporting plates |34, as at |54.

rlhe triangular-shaped links |52 are connected with an actuating collar which is slidably mounted on actuating rod 16, by means of a pair of connecting links |56, pivotally connected with links |52 as by a pivot pin |58, and pivotally connected with the actuating collar as at |62.

The electrical circuit through the circuit breaker shown in Fig. 1 extends from the covei` terminal I0 through bracket cover I8, through a conductor |63 to solenoid coil H8, then by Way of a exible conductor (not shown) to contact actuating rod 16, to fixed contact 88, compression spring 86, terminal bolt 6, to terminal I4. Solenoid coil I8 is, therefore, connected in series in the circuit through the interrupter so that upon the passage of current through the circuit above a predetermined value, the solenoid will attract core ||4 with suflicient force to cause it to move upwardly at a rate determined by the rate of escape of liquid through dashpot vent |28. This upward movement of solenoid core ||4 causes lever |38 to be moved in a counterclockwise direction about its suporting pivot |40, and tensions overcenter spring |48. As soon as spring |48 is moved in a counterclockwise direction past the center line of spring supporting pin |50 and pivot |54 for'the triangular-shaped links, the spring will then exert a force on the triangular-shaped links in a direction to cause clockwise movement of these links about their pivots |54, and thereby cause upward movement of connecting links |56 and sliding of actuating collar |60 along the Contact actuating rod into engagement with head |64, to thereby cause movement of contact |06 away from fixed contact 88. It will be observed that no force is applied to separate the contacts until spring |48 is moved overcenter, when the full force of the stressed spring is suddenly exerted to separate the contacts against the bias of their biasing spring 62. The amount of contact separation produced by overcenter spring |48 may obviously be regulated any desired amount. However, this amount shoud be sufficient to obtain at least a predetermined amount of contact separation such that an appreciable delay occurs before the contacts are reclosed by biasing spring 62. This is accomplished by the use of the mechanism described by storing energy in overcenter spring |40 during the rst part of the movement of solenoid core 4, and then suddenly releasing this energy to separate the contacts, so that the rate of contact separation and the distance of separation will be entirely independent of the rate of movement of the solenoid core, or the force developed by solenoid coil H8.

As soon as the contacts separate, an arc is established between them and pressure developed thereby will exert an additional contact-separating forcethe value of which depends upon the current value of the arc. The position of the overcenter spring and parts associated therewith is shown in Fig. 3 of the drawings, when these parts have moved to the positions they occupy when the contacts are separated. It will be observed that because there is lost motion of actuating collar |50 on the contact operating rod, that after the contacts are separated the amount predetermined by actuation or" overcenter spring |48, movable contact |04 may then further separate from liked contact 88 by sliding movement of contact actuating rod 16 in actuating collar |60. However, as soon as the arc is extinguished, solenoid coil H8 will be deenergized, and biasing spring 52 will then be free to reclose the contacts. If movable Contact 05 has travelled beyond the position the contact actuating rod occupies in Fig. 3, biasing spring 62 will quickly restore it to the position shown in Fig. 3. However, it will be noted that further reclosing cannot occur because the toggle comprising connecting links 56 and triangular links |52 is held at an overcenter position by spring |48. However, solenoid core H4 and actuating sleeve |30 will then be slowly returned to their normal position by compression spring |24, the rate of return being determined by the size of vent |28 for dashpot cylinder |20. This results in gradual movement of lever |38 in a clockwise direction, and it eventually moves spring |48 back below pivot |54, to thereby break the toggle holding the contacts open and thus assist biasing spring S2 in rapidly reclosing the contacts.

In order to limit the number` oi successive circuit interrupting operations which can take place in the event a continuing fault appears on the circuit, there is provided integrating means for counting the number of closely succeeding circuit interrupting operations, preferably mounted on a suport |65 secured to Supporting plates |34. The suport |06 carries a cylindrical tube |58 in which is mounted an integrator piston |10 having notches |12 therein which are accessible through a side opening in the upper end of tube |68, so as to be engaged by an actuating pawl |14. Pawl |14 is generally U-shaped in form, and has the lower leg thereof apertured to be slidably mounted on a guide rod |15 also secured on support |65, and has the upper leg slotted to receive the guide rod, but permitting tilting of the uper end of the pawl into and out of engagement with notches |12. A coil compression spring |18 mounted on the guide rod is adapted to normally maintain the pawl in the position shown, where it is out of engagement with integrator piston |10.

In the operation of the circuit breaker, each time lever |38 is moved in a counterclockwise direction to its upper position designated by dotted line |8|, it engages pawl |14 and moves it upwardly on guide rod |15. The engagement of lever |38 with pawl |14 also causes the upper end of the pawl to enter a notch |12 in the integrating piston, and move the piston upwardly with the pawl an amount roughly equal to the distance .between notches |12. Support ld is provided with a fluid-inlet opening for cylinder |68, which permits ilow solely inwardly by virtue of a ball-check valve seated over opening |80 within tube |68. Upon reclosure or" the circuit breaker following an interrupting operation, pawl |14 is returned to its original position shown in Fig. 1 by spring |18, while integrator piston remains at the position to which it has been advanced, returning very slowly to its original position shown in Fig. 1 due to the necessity of displacing liquid which has been drawn into the bottom of tube |68 past the rela.- tively small clearance between the piston and tube |58. If after the reclosing operation the fault has cleared, piston |10 will eventually sink to its original position. However, if the fault or overload condition is still present upon reclosure of the circuit breaker, it will immediately reopen, and this time pawl |14 will engage the next lower notch |12 on the integrator piston. This will cause the piston to be raised upwardly a further amount, substantially into engagement with toggle link 44. Upon the second closely succeeding reclosure of the breaker, if the overload condition has disappeared, the integrator piston will again slowly sink to its original position. However, if the overload condition is still present on the circuit, the breaker will again open immediately, and this time pawl |14 will engage the lowest notch in the integrator piston, and move the piston upwardly until extension |82 thereof engages toggle link 44 and `moves it upwardly to collapse toggle links 42 and 44, and thereby permit spring 32 to rotate spring support 30 in a direction to maintain the breaker contacts open, and render reclosing spring 62 inoperative. This, of course, will be accompanied by movement of extension 52 of toggle link 44 downwardly, so that it will project below hood SS-'and present a readily visible indication of the locked-open condition of the breaker.

In the embodiment of the invention shown in Figs. 4 and 5, contact head |05 is adapted to engage a stationary Contact which has some resiliency to provide the necessary contact pressure. Preferably, this is accomplished by a staticnary contact structure which includes a contact bolt |94 having a head |90 thereon, with the bolt secured in position by a nut |35. A contact cup |92 is telescoped over the head |90 of bolt |84, and is normally biased toward the movable contact by a compression spring |94, which is maintained in compressed condition when the contacts are closed, as shown in Fig. 4.

In this embodiment of the invention, actuating sleeve |30 which is attached to the solenoid core, is connected by links |42 with levers |99, as by pivot pins |96. The levers |98 are pivoted at their opposite ends on supporting pins 200, and an overcenter spring 202 is connected at one end with pivot pin |96, and at its other end engages a pin 204 connecting generally triangularshaped links 206. The triangular-shaped links 20S are pivotally mounted on a fixed support as at 208, and are connected to movement multiplying levers 2| 6, by connecting links 2|0, pivoted to the triangular links as at 2|2, and to the levers 2|6 as by a pivot pin 2|4. The levers 2|6 are supported by a pivot pin 2|8, and are connected to contact actuating rod 10 by links 222, pivoted to levers 2|6 as at 220, and to the Contact actuating rod by a pivot pin 224.

It will be noted that in the closed position of the contacts, overcenter spring 202 maintains the toggle comprising levers 205 and 2|0 at an overcenter position against a fixed stop 2H. This holds the contacts in engagement with contact pressure spring |94 compressed a predetermined amount to provide a predetermined contact pressure. When an overload condition appears on the circuit and the solenoid core is attracted upwardly to move links |42 upwardly and levers |98 in a counterclockwise direction, spring 202 will be placed under further tension,

but the contact pressure will be unchanged ldue to the extended overcenter condition of toggle levers 206 and 2l0. Eventually spring 202 will ibe moved past pivot point 208, whereupon it will bey veffective to rotate links 206 in a clockwise direction, and thus break the toggle formed by levers S and Bill. Thus, pressure is maintained at a predetermined value on the contacts until after spring 202 moves over the center of Vpivot point 208, and as soon as this occurs, clockwise rotation of the links 241i` induced by the spring will cause connecting links 2 I0 to .be pulled upwardly and levers 2I6 to rotate in a counterclockwise direction, thereby moving connecting links 222 upwardly to move contact 106 away from contact cup l92. This means that predetermined pressure is maintained on the contacts until actual contact separation occurs.

Toggle levers` 42 and 44 may also be provided in connection with this embodiment of the invention for maintaining the breaker contacts in opencircuit position when the toggle is broken, and in this instance, toggle lever 44 is preferably provided with an integral extension 226, which engages with adjustable stop screw 54, tok maintain the toggle in extended condition under the stress of coil spring 234, which reacts at one end against a fixed support 238, and at its other end against a pin 236 on crank 230 pivotally connected with toggle lever 42 as at 23|. Crank 235 is pivotally mounted on xed pivot 232'.- A hook eye 228 is provided in the outer end of extension 226, for permitting manual operation and resetting. Since contact pressure, in the embodiment of ther invention shown in Figs. 4 and 5, is maintained by the operating mechanism and by overcenter spring 202, but a relatively weak spring 240 need be employed to eiiect a reclosing operation, since all this spring needs to do is to move spring 2532 back overcenter to the position shown in l'llig. e. Accordingly, reclosing spring 240 is mounted on a guide rod 242 pivotally connected at one end with levers 98 as by a pivot pin 244', and having a slot 248 in its other end for receiving pivot pin 231i of toggle link 42. Spring guide rod is provided with collars 248 between which spring 21536 reacts, to normally bias levers 98 in a clockwise direction.

After a circuit opening operation, and when the solenoid becomes deenergized due to extinguishing of the arc, spring 240 will then be free to rotate levers E98 in a clockwise direction to move spring 202 back overcenter ytoward the position shownin Fig. 4. This movement, however, will be resisted by the dashpot action of the solenoid core, so that a predetermined time delay will be inserted between circuit interruption and reclosure of the breaker contacts.

In the embodiment of the invention shown in Figs. (i and 7, contact actuating rod 16 is provided with an actuating pin 250 secured thereto, which is adapted to be actuated by an actuating link 252, having an open-ended slot with one short side 256, and a long side 254, for receiving pin 250 therebetween. The movement of actuating lever 252 is controlled by a supporting link 258 pivotally connected with the actuating link as at andv pivoted on a support as at 262. The supporting link 253 preferably is provided with an integral, laterally extending stop flange 260, for a purpose to be described. Movement of the actuating link 252 is also controlled by a secondlink d pivotally connected with the actuating link as by a pvot pin 266, and mounted on a support by means of the pivot pin 200. The actuating link 252 is operated by means of an overcenter compression spring 268 mounted within a tubular spring housing 270, which is pivotally mounted on pivot pin 265, and has the other end thereof slotted as at 214, for receiving an actuating pin 212 provided on lever E08. y

In the operation of the embodiment of the invention shown in Figs. 6 and 7, it is apparent that in the closed circuit position (Fig. 5), spring 268 assists the reclosing spring in holding the contacts closed. In opening the circuit, lever 198 is moved upwardly in a counterclockwise direction in the same way as in the embodiment of' the invention shown in Figs. 4 and 5. This causes compression of overcenter spring 258, until the spring passes over pivot point 259, whereupon supporting lever 204 is moved downwardly in a clockwise direction, this causes pivotal movement of actuating link 252 in a counterclockwise direction about its pivot 259 to thereby move contact actuating rod iii upwardly to separate the breaker contacts. Continued clockwise rotation of supporting link 204 nally causes movement of actuating link 252 away from pin 250 at least enough to clear the upper leg 255i, to the posit-ion illustrated in Fig. 'i where actuating link 252 engages stop ange 260. At this position, it

is clear that contact actuating rod 'It may continue its circuit opening movement, and have overtravel with respect to the overcenter spring and its actuating linkage, any desired amount. However, when the circuit has been interrupted, and contact actuating rod 16 returns toward closed circuit position, pin 250 will engage lower leg 254 or" the actuating link, and further closing movement will be delayed by the dashpot action of the solenoid core connected with links i442, until'overcenter spring 2&8 is moved back overcenter toward the position shown in Fig. 6.

In all the embodiments of the invention disclosed, means are provided for preventing pumping action of the breaker contacts by requiring at least a predetermined amount of contact separation, at a predetermined rate, irrespective of the rate of movement of the electroresponsive actuating means, or the amount of force generated thereby. Thus, on very low current overloads, the contacts will be separated at least a predetermined distance and at a predetermined rate of speed suiicient to allow enough time delay before reclosure to permit clearing of the fault, if it be of the self-clearing type, and to prevent too rapid opening and reclosing of the breaker contacts. At the same time, the minimum contact separation provided 'is so arranged as to always actuate the integrating counting mechanism so that upon a predetermined number of closely succeeding circuit interrupting operations, the breaker contacts will be maintained in open circuit position. In general, this is accomplished by the provision of overcenter spring actuating mechanism moved in the direction to open the circuit by electroresponsive means, and in the opposite direction by a reclosing spring. In accordance with thisinvention, the contact actuating mechanism may be associated with the movable contact in such a manner as to permit overtravel of the contact with respect to the mechanism, for example, as by the lost motion connection in the species of Figs. 1 to 3, or by the releasable connection in the species of Figs. 6 and 7. Moreover, the contact actuating mechanism embodying an overcenter spring may utilize such spring to maintain pre- 1l determined pressure on the breaker contacts until they are actually separated, and in lieu of a heavy reclosing spring, a relatively light spring 'may bev used merely to reset the overcenter spring mechanism.

Having described preferred embodiments of the invention in accordance with patent statutes, it is desired that the invention be not limited to these particular embodiments, because it will be obvious to persons skilled in the art that many modifications and changes may be made in these particular embodiments without departing from the broad spirit and scope of this invention.

We claim as our invention:

1. An automatic reclosing circuit breaker comprising, separable contact means one oi which is mounted for movement into and out of engagement with the other, operating means for said movable contact means comprising, electroresponsive means which is movable in response to a predetermined electrical condition of the circuiti tol separate said contact means and interrupt the circuit, overcenter spring means interposed between said electroresponsive means and Said movable contact means so as to be moved o vercenter in response to such movement to separate said contact means, means responsive to a circuit opening operation for automatically reclosing said contact means, means actuated by said overcenter spring in response to movement gagement with the other, operating means -for said movable contact means comprising, electroresponsive means which is movable in response to a predetermined electrical condition of the circuit to separate saidcontact means and interrupt the circuit, means interposed between said electroresponsive means and said movable contact means which is normally operable to provide a predetermined pressure between said contact meansand is responsive to the aforesaid movement of saidelectroresponsive means to store energy during the n-rst part of such movement and thereafter release such energy to separate said contact means, means dependent upon the current value of the arc formed upon separation of said contactstoexert additional contact-separating force on said` movable contact means to thereby obtain a contact openingspeed which varies from a minimum determined.- by said stored energy on low currents in accordance with the value of current interrupted, a lost motion connection between said interposed means and said movable contact means s'o that said movable contact means may have overtravel relative to said interposedmeans during a circuit opening operation, andmeansresponsive to a circuit opening operationfor automatically reclosing said contact means.

3. An automaticreclcsing circuit breaker comprising, separable contacts, electroresponsive means movable in one direction in response to a predetermined electrical condition of the circuit for causing. separation of said contacts, toggle means. comprising a pairof toggle levers pivotally connected together at one end of each lever to form a knee` pivot, one of. said levers having a lost motion connection at a remote point to o of said contacts, the other of said levers beim pivoted at a remote point on a stationary Support so as to be movable to one overcenter polition to separate said contacts, and into engagement with a stop member to lock the contacts at an open circuit position, and a spring oonnected between said toggle means and said eleotroresponsive means so as to be moved overcenter in one direction in response to. predo- 'termined movement of said electroresponsivc means to move said toggle means to its said one overcenter position to separate said contacts and lock said contacts separated at least a. predetermined distance apart, means responsive to a circuit opening operation to move said spring overcenter in the other direction to permit automatic reclosure of said contacts, and time delay means for delaying the last-mentioned movement of said overcenter spring,

4. ln an automatic reclosing circuit breaker, separable contacts, electroresponsive means having lost motion with respect to said contacts so as to movable in response to a predetermined electrical condition of the circuit a predetermined distance before causing separation of said contacts, said contacts being biased in a direction to automatically reclose in response` to a circuit interrupting operation and to` provide. a predetermined contact pressure when closed, a. spring connecting said electroresponsive means and one of said contacts adapted to` be moved; overcenter in response to predetermined movement of said electroresponsive means to.separatesard-` contact-s at least a predeterminedl distance and at a rate independent ofthe rate of movement of said @responsive means and the amount of force exer d thereby, means independent of said closing bias to move said spring overcenter inthe opposite direction topermit reclosure ofsaid contacts, and time delay means for delayingy movement of said spring overcenter at least inone direction.

5. En an automatic reclosingcircuit breaker, separable contacts, electroresponsive means-movable in response to a predetermined electricallcondition of the circuit for causingseparation-fof contacts, said contacts being biased in a direction to automatically reclose in' responseto a circuit interrupting operation, a spring adapted to be moved overcenter in response to predeterminedl movement of said electroresponsive means to separate said contacts at least a predetermined distance and at a rate independent ofv the rate ci movementof said electroresponsive means and theamount off force exerted thereby, saidI spring having connection with at least one or said contacts which` is separable` response to` said predetermined contact separation topermit overtravel ofy said contacts in a circuit interrupting operation independent of said spring and electroresponsive means and meansoperable to effect over-travel of saidy contacts in accordance with the current value-oi an arc formed'upon separation of said contacts.

6. In an automatic reclosing4 circuit breaker, separable contacts, electroresponsive means movable inresponseto apredetermined.electrical condition or" the circuit for-causing separation of said contacts, said contacts being biased inA a direction to automatically reclose in response to a circuit interrupting operation, and springmeans interposed between said electroresponsive means and said contactsandnormally-operable toprovide a predetermined pressurebetween said contact means and is operable in response to predetermined movement of said electroresponsive means to rst store and then release a predetermined amount of energy which is at least greater than the force biasing said contacts closed, to separate said contacts at least a predetermined distance and at a rate independent of the rate of movement of said electroresponsive means and the amount of force exerted thereby, said interposed means having a connection With at least one of said contacts which is separable in response to said predetermined contact separation to permit overtravel of said contacts in a circuit interrupting operation independent of said spring means and electroresponsive means.

7. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means having lost motion With respect to said contacts so as to be movable in response to a predetermined electrical condition of the circuit a predetermined distance before causing separation of said contacts, said contacts being biased in a direction to automatically reclose in response to a circuit interrupting operation and to provide a predetermined contact pressure when closed, a spring connecting said electroresponsive means and one of said contacts and adapted to be moved overcenter in response to predetermined movement of said electroresponsive means to separate said contacts at least a predetermined distance and at a rate independent of the rate of movement of said electroresponsive means and the amount of force exerted thereby, and means independent of said closing bias and connected to said spring to move said spring overcenter in the opposite direction to permit reclosure of said contacts.

8. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means movable in response to a predetermined electrical condition of the circuit for causing separation of said contacts, said contacts being biased in a direction to automatically reclose in response to a circuit interrupting operation, a spring adapted to be moved overcenter in response to predetermined movement of said electroresponsive means to separate said contacts at least a predetermined distance and at a rate independent of the rate of movement of said electroresponsive means and the amount of force exerted thereby, said spring having a connection with at least one of said contacts which is separable in response to said' predetermined contact separation to permit overtravel of said contacts in a circuit interrupting operation independent of said spring and electro.. responsive means, and said separable connection being automatically reestablished by reclosure of said contacts to move said spring overcenter in the opposite direction.

9. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means movable in response to a predetermined electrical condition of the circuit for causing separation of said contacts, said contacts being biased in a direction to automatically reclose in response to a circuit interrupting operation, a movable actuating member for said contacts having a pin and open-end slot connection with at least one of said contacts, an overcenter spring actuated by said electroresponsive means for moving said actuating member at least in a circuit opening direction, means guiding the movement of said actuating member so as to cause separation of said contacts a predetermined distance during the rst portion of its movement and thereafter cause movement of said actuating member so as to permit escape of said pin from the open end of said slot upon continued separation of said contacts, and means to cause said pin to reenter said slot in response to reclosure of said contacts to cause movement of said spring overcenter in the opposite direction.

10. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means movable in response to a predetermined electrical condition of the circuit for causing separation of said contacts, a movable actuating member for said contacts having a pin and open-end slot connection with at least one of said contacts, an overcenter spring actuated by said electroresponsive means for moving said actuating member at least in a circuit opening direction, means guiding the movement of said actuating member so as to cause separation of said contacts a predetermined distance during the first portion of its movement and thereafter cause movement of said actuating member so as to permit escape of said pin from the open end of said slot upon continued separation of said contacts, and means to cause said pin to reenter said slot in response to reclosure of said contacts to cause movement of said spring overcenter in the opposite direction.

11. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means movable in one direction in response to a predetermined electrical condition of the circuit for causing separation of said contacts, toggle means connected between one of said contacts and a stationary support so as to be movable to one overcenter position to separate said contacts, and into engagement with a stop member to lock them at an open circuit position, a spring connected between said toggle means and said electroresponsive means so as to be moved overcenter in one direction in response to predetermined movement of said electroresponsive means to move said toggle means to its said one overcenter position to separate said contacts and lock said contacts separated at least a predetermined distance apart, and resilient means stressed by said electroresponsive means during the aforesaid predetermined movement thereof for moving said spring ove-rcenter in the other direction to permit automatic reclosure of said contacts.

JAMES M. WALLACE. ALVIN W. OGG.

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